Electrical indicating device.



' No. 839,690.; PATENTED DEC. 25, 1906.

e. ZAPP. ELECTRICAL INDIOATING DEVICE.

APPLICATION FILED MAR. 28, 1905.

ELECTRICAL INDICATING DEVICE.

Specification of Letters Patent.

Patented Dec. 25, 1906,

Application filed March 28,1905. Serial No. 252,566.

To all whom it may concern:

Be it known that I, GEORG ZAPF, engineer, a subject of the German Emperor, residing at Cologne-Nippes, Province of the Rhine, Empire of Germany, have invented certain new and useful Improvements in Electrical Indicating Devices, of which the following is a specification.

In means for protecting conductors against overcharging in which a discharge to the earth takes place without the conductor itself being interrupted, but in which after such a discharge it is necessary or desirable to change or repair certain parts, it is of course felt to be a drawback that the discharge which has taken place is not indicated, and where a large number of safety devices are connected to the conductor the inspector does not know at which of these devices the discharge has taken place. This drawback is most felt in safety devices for subterranean cables, in which the safety devices are not immediately accessible nor easily inspected.

The object of the present invention forms a means for indicating and notifying such discharges.

In the drawing, (t represents an underground cable, I) spark-gap safety devices of any suitable kind which are intercalated in earthed wires 0. From these wires a wire (Z is branched off, which wire lies above or below the ground, all of which wires (1 lead to a common annunciator 6, provided with a bell or other signaling device. Preferably these wires are branched oil from the last coils of the resistances w, inserted in the earthed wires 0 with the object of diminishing the current strength, the resistance w being situated between the conductor a and the signaling device 6. A wire is carried to the earth from the annunciator e.

If a discharge takes place at one of the safety devices, the difference of potential arising between the branching point of the respective wire (Z and the earth-pole E of the annunciator (2 causes the bell to sound and a corresponding number-flap to drop. The strength of the current passing into the wires (i may be regulated at will by interposing suitable resistances.

Having now particularly described and as certained the nature of my said invention and in what manner the same is to be per formed, I declare that what I claim is- Means for indicating the discharge from a spark-gap safety device comprising the combination with a spark-gap safety device intercalated into an earthed wire, of a branch wire connected with the earthed wire and leading to a signaling device, and a resistance arranged between the signaling device and the spark-gap safety device.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

GEORG ZAPF. W'itnesses:

VVILLIAM KUEPPERs, YOK SonoLZ. 

